This paper aims to investigate the process of presupposition accommodation and its ramifications to the context. Among global accommodation and local accommodation Heim (1983) suggests, local accommodation accounts for the case of defeasible presuppositions which poses a problem for the filtering theories of presupposition against the cancellation theories. Although it has been claimed that global accommodation is generally preferred unless it causes infelicity, this study maintains that local accommodation also has explanatory power and that contextual factors play an important role than mere preference for global accommodation in determining which type of accommodation is selected. This study also points out that language users choose a type of accommodation and apply it in such a way that the common ground is amended in order to enhance its consistency. (Ewha Womans University).